David W. Schloerb

A quantitative measure of telepresence

This paper presents the foundation for a theory of presence that seeks to answer important questions about telepresence and virtual presence. The theory, which develops the definition of telepresence to include virtual presence as a special case, permits the precise definition of various types and degrees of telepresence. General categories of telepresence are defined, using different types of presence that are proposed in the paper. Three types of specifications are used to make the definitions more precise: (1) a set of tasks, (2) a transformation imposed on the human operators control output and sensory input, and (3) a transformation of the region of presence. The proposed quantitative measure of telepresence involves both objective and subjective measures. The degree of (objective) telepresence is equal to the probability of successfully completing a specified task. The degree of subjective telepresence is equal to the probability that a human operator perceives that he or she is physically present in a given remote environment. The measure of subjective telepresence involves a psychophysical test and is analyzed using signal detection theory. Real-world complications are addressed and a practical example of a subjective telepresence test is described.

BlindAid: Virtual environment system for self-reliant trip planning and orientation and mobility training

BlindAid is a virtual environment (VE) system that enables blind people to more easily learn about new environments on their own. The system is implemented on a desktop personal computer with a Phantom? haptic interface and three-dimensional spatialized audio. In addition to providing blind users with non-visual stimuli similar to what they will depend on in the actual environment, the system is designed to enhance and accelerate the users understanding of the unknown environment by giving him/her the ability to interact with the VE in ways that are not possible in the real world. The BlindAid system was developed and evaluated as part of an experimental study related to how people who are blind build cognitive maps of their physical environment and how recent advances in VE technology might support orientation and mobility (O&M) training. The current system is able to provide a visual display and record the users actions in the VE for later review by researchers and O&M instructors. The paper focuses on the technical development of the system with some results from an initial evaluation by four blind volunteers.

Virtual Workbench: Near-Field Virtual Environment System with Applications

A prototype near-field virtual environment system is described that incorporates a CrystalEyes stereoscopic display (viewed in a mirror), a PHANToM manipulandum, and a stereo auditory display. The apparatus, which was designed to achieve registration of three sensory modalities (visual, haptic, and auditory), has a wide range of applications and has been used for both psychophysics and training research. Calibration-verification experiments are described in which human subjects positioned a physical probe attached to the manipulandum so that it appeared to coincide with a visual target on the stereoscopic display. The readings from the manipulandum and the calculated positions of the targets corresponded roughly within 0.5 cm over a large volume, although differences greater than 1 cm were observed near the sides of the workspace. The calibration of the manipulandum was tested independently on the z axis (running through the center of the workspace), and the perceived depth of the targets (probe z coordinate) was found to agree with the calculated depth within the accuracy of the measurements ( 0.4 cm). Some subjects had poorer positioning resolution when the visual target was far from the plane of the display screen (although their mean response was unaffected), and we hypothesize that this may have been caused by the different levels of accommodation that were needed to view the physical probe and the displayed target.

Newly blind persons using virtual environment system in a traditional orientation and mobility rehabilitation program: a case study.

This paper presents a virtual reality system (the BlindAid) developed for orientation and mobility training of people who are newly blind. The BlindAid allows users to interact with different virtual structures and objects via auditory and haptic feedback. This case study aims to examine if and how the BlindAid, in conjunction with a traditional rehabilitation programme, can help people who are newly blind develop new orientation and mobility methods. Follow-up research based on this study, with a large experiment and control group, could contribute to the area of orientation and mobility rehabilitation training for the newly blind. The case study research focused on A., a woman who is newly blind, for 17 virtual sessions spanning ten weeks, during the 12 weeks of her traditional orientation and mobility rehabilitation programme. The research was implemented by using virtual environment (VE) exploration and orientation tasks in VE and physical spaces. The research methodology used both qualitative and quantitative methods, including interviews, questionnaire, videotape recording, and user computer logs. The results of this study helped elucidate several issues concerning the contribution of the BlindAid system to the exploration strategies and learning processes experienced by the participant in her encounters with familiar and unfamiliar physical surroundings. Implications for Rehabilitation This case study shows that people who are newly blind can use VE simulation as part of their rehabilitation training. The ability to undergo training in the VE concurrently with the traditional O & M rehabilitation programme enabled people who are blind to practise O & M methods in the VE simulation and, through this, to increase their sense of control and confidence. The VE enabled the people who are newly blind to transfer their exploratory strategies and methods from the real space to the VE and back again to the real space. The VE can be used as a preplanning aid to explore unknown spaces in advance before orienting in the real space

BlindAid: A learning environment for enabling people who are blind to explore and navigate through unknown real spaces

In our everyday lives the fundamental role played by sensory systems, such as vision, hearing, and touch, is often taken for granted. Most of the information for the cognitive mapping of spaces used by people who are sighted is gathered through the visual channel. Unfortunately, people who are blind or have low vision lack the ability to collect the required visual information either in advance or in-situ. Indeed, for people who are blind an unknown environment can be unpleasant, uncomfortable, and unsafe even after extensive orientation and mobility rehabilitation training. In this study we developed a new virtual environment system for people who are blind to aid them in their anticipatory exploration and cognitive mapping of unknown environments. The two main goals of the study were: (1) to develop and assess an integrated haptic and audio virtual environment system though which people who are blind can explore a virtual map of an unknown real space and (2) to study the cognitive mapping process of people who are blind when using the virtual environment. The findings supply strong evidence that interaction with the BlindAid system by people who are blind provided a robust foundation for the participantspsila development of comprehensive cognitive maps of real unknown spaces. In conjunction with these results, the userspsila performance within the virtual environment supplied an assessment tool for orientation and mobility specialists. (Supported by a grant from National Eye Institute, NIH.).

A virtual environment for people who are blind – a usability study

For most people who are blind, exploring an unknown environment can be unpleasant, uncomfortable, and unsafe. Over the past years, the use of virtual reality as a learning and rehabilitation tool for people with disabilities has been on the rise. This research is based on the hypothesis that the supply of appropriate perceptual and conceptual information through compensatory sensorial channels may assist people who are blind with anticipatory exploration. In this research we developed and tested the BlindAid system, which allows the user to explore a virtual environment. The two main goals of the research were: (a) evaluation of different modalities (haptic and audio) and navigation tools, and (b) evaluation of spatial cognitive mapping employed by people who are blind. Our research included four participants who are totally blind. The preliminary findings confirm that the system enabled participants to develop comprehensive cognitive maps by exploring the virtual environment.

Rehabilitation Program Integrating Virtual Environment to Improve Orientation and Mobility Skills for People Who Are Blind.

This paper presents the integration of a virtual environment (BlindAid) in an orientation and mobility rehabilitation program as a training aid for people who are blind. BlindAid allows the users to interact with different virtual structures and objects through auditory and haptic feedback. This research explores if and how use of the BlindAid in conjunction with a rehabilitation program can help people who are blind train themselves in familiar and unfamiliar spaces. The study, focused on nine participants who were congenitally, adventitiously, and newly blind, during their orientation and mobility rehabilitation program at the Carroll Center for the Blind (Newton, Massachusetts, USA). The research was implemented using virtual environment (VE) exploration tasks and orientation tasks in virtual environments and real spaces. The methodology encompassed both qualitative and quantitative methods, including interviews, a questionnaire, videotape recording, and user computer logs. The results demonstrated that the BlindAid training gave participants additional time to explore the virtual environment systematically. Secondly, it helped elucidate several issues concerning the potential strengths of the BlindAid system as a training aid for orientation and mobility for both adults and teenagers who are congenitally, adventitiously, and newly blind.

Experimental investigation of the relationship between subjective telepresence and performance in hand-eye tasks

In this quantitative investigation of telepresence human test subjects performed a 2 dof manual task, similar to a Fitts task, and then responded to questions about the experience after each trial. The task involved using a position input device to manipulate a virtual object on a computer screen. The experimental arrangement made it possible to modify the relationship between what the subjects hand did and what his/her eyes saw. Three different control/sensory transformations were investigated: time delay, rotation, and linear scaling. The subjects responses were used as the basis for measuring the degree of subjective telepresence (equal to the probability that the human operator will detect the transformation). Subjects also made a direct subjective rating of the transformation in one experiment. Task time served as the measure of task performance. No general relationship between subjective telepresence and task performance was discovered.

Virtual Environment System in Support of a Traditional Orientation and Mobility Rehabilitation Program for People Who Are Blind

BlindAid, a virtual environment system developed in part for orientation and mobility training of newly, adventitiously, and congenitally blind persons, allows interaction with different virtual structures and objects via auditory and haptic feedback. This research examined whether and how the system might help people who are blind develop orientation and mobility skills within a traditional rehabilitation program. Nine clients at The Carroll Center for the Blind (Newton, MA) explored VEs and performed virtual orientation tasks in addition to their traditional orientation and mobility training. The virtual training gave the participants additional time to learn systematic exploration and orientation strategies and their performance was evaluated using qualitative and quantitative methods. The findings supply strong evidence that practicing with the BlindAid system does enhance traditional orientation and mobility training in these areas.